WO2010116529A1 - Tank and fabrication method thereof - Google Patents

Abstract

The objective is to provide a tank and a fabrication method thereof that keep the physical constitution or mass of a tank from being increased by fiber layers, such as helical layers. To realize this, a tank (1) comprises a liner (20) and an FRP layer (21), which is made from hoop layers (70P) and helical layers (70H) that are formed by fiber bundles (70) being wrapped around the outer circumference of said liner (20). The percentage of the body part (1s) of the tank (1) covered by the fibers (70) of helical layers (70H) is made lower in the outer layers than in the inner layers of the FRP layer (21). It is preferable that the percentage of coverage by helical layers (70H) decreases continuously. Alternatively, it is preferable that the percentage of coverage by helical layers (70H) decreases in a stepwise fashion.

Description

Tank and manufacturing method thereof

The present invention relates to a tank and a manufacturing method thereof. More specifically, the present invention relates to an improvement in the structure of a tank filled with hydrogen gas or the like at a high pressure.

As a tank used for storing hydrogen gas or the like, a tank that is provided with an FRP layer in which a plurality of hoop layers and a helical layer are laminated on the outer periphery of the liner and is reduced in weight is used (for example, see Patent Document 1). ). The liner functions as a member that prevents permeation of hydrogen gas and the like and stores it in an airtight manner, and the FRP layer functions as a member that provides strength to withstand high internal pressure.

The hoop layer forming the FRP layer is a layer formed by winding a fiber (for example, carbon fiber) by hoop winding (a method of winding the fiber around the tank axis in the tank body portion). (It is substantially parallel to the tank axis and is wound up to the tank dome.) (See FIG. 2). Further, helical winding can be performed in different manners such as high angle helical winding and low angle helical winding by changing the winding angle with respect to the tank axis. When forming the FRP layer in this manner, how the fibers are wound is an important factor for improving the efficiency of strength expression by the FRP layer.

Conventionally, as a specific method of winding fibers, for example, a circumferential fiber layer (hoop layer, high-angle helical layer) and an axial fiber layer (low-angle helical layer) are alternately wound. is there. In this case, for example, since the entire surface is covered with the fibers constituting the axial fiber layer (low-angle helical layer) without any gap, the fiber coverage is 100% or more. The fiber coverage here refers to the ratio of the one-sided surface area of the fiber wound around the layer to the surface area of the tank body part (surface area of the fiber wound around the layer / body part surface area). It can be determined by x100. The coverage when the entire surface area of the body portion is covered with the minimum necessary fibers is 100%. In the conventional technique, when the fiber layers are laminated, the fibers are generally wound so that the covering ratio is 100% or more in all the helical layers. Incidentally, the tank is a sealed container in which, for example, both ends of a cylindrical main body part are formed in a substantially hemispherical dome part. In this specification, a substantially hemispherical part is a dome part, and a cylindrical body part is a body part ( Or straight part).

JP 2008-032088 A

However, in the conventional tank as described above, there is a problem in that the size and mass of the tank are increased by a fiber layer such as a helical layer laminated on the outer layer side.

Therefore, an object of the present invention is to provide a tank that suppresses an increase in the size or mass of the tank due to a fiber layer such as a helical layer, and a manufacturing method thereof.

The present inventor has made various studies to solve such problems. As described above, a general method is to form a fiber layer by winding a circumferential fiber layer (hoop layer, high-angle helical layer) and an axial fiber layer (low-angle helical layer) around the liner. However, when the fiber layers are laminated in this way, it is considered that the outer fiber layers are more difficult to fully exhibit the strength of the fibers. Further, if the fibers are wound without sufficiently exerting the strength, the amount of fibers is large for the strength, and the tank may have a large physique. In particular, the fiber wound on the outer layer side can contribute to an increase in the tank diameter if it is wound many times even though the contribution to the strength is small.

The present inventor who has further studied based on such a situation has come to obtain new knowledge that leads to the solution of such problems. The present invention is based on such knowledge, and is a tank having a liner, and a FRP layer composed of a hoop layer and a helical layer formed by winding fibers on the outer periphery of the liner, and depends on the fibers of the helical layer. The cover rate of the tank body is lower on the outer layer side than on the inner layer side of the FRP layer.

The layer located on the outer layer side of the tank and the helical layer have a small contribution in terms of fiber strength with respect to the cylindrical body part (tank body part) of the tank. That is, the fiber layer located on the outer layer side or the helical layer at a lower angle is more difficult to exert the strength of the fiber and to tightly wind the body portion of the tank. On the other hand, according to the helical layer in the cylindrical body part, it is possible to exert a fiber strength greater than that of the helical layer. Nevertheless, the uniform coverage by the fibers as in the conventional method is disadvantageous in that it is difficult to obtain sufficient fiber strength for the increased amount of fibers used. In this respect, in the tank according to the present invention, by increasing the coverage of the body portion by the helical layer toward the inner layer side, the fiber strength generation rate in the helical layer (in order to act the force against the tank internal pressure) The degree to which the strength of the fiber is generated is effectively improved. In such a case, it is possible to reduce the amount of fiber used while realizing a high fiber strength occurrence rate, and to prevent the tank from becoming larger (larger).

Also, if the amount of fiber used can be reduced while realizing a high fiber strength occurrence rate, the FRP layer can be made thinner and the volume of the tank can be increased. Alternatively, it is possible to reduce the diameter of the entire tank while maintaining the volume.

In the tank described above, it is preferable that the coverage by the helical layer is continuously reduced. Or it is also preferable that the coverage by a helical layer is decreasing in steps.

Further, in the above-described tank, the rate of decrease in the coverage rate may be constant. Alternatively, the rate of decrease in the coverage rate may change midway.

The manufacturing method according to the present invention is a method for manufacturing a tank having a liner and an FRP layer comprising a hoop layer and a helical layer formed by winding fibers on the outer periphery of the liner. When this is done, the coverage of the tank body by the helical layer is made lower on the outer layer side than on the inner layer side of the FRP layer.

According to the present invention, it is an object to provide a tank and a method for manufacturing the same in which the physique or mass of the tank is prevented from being increased by fibers such as a helical layer.

It is sectional drawing and the elements on larger scale which show the structure of the tank in one Embodiment of this invention. It is a figure for demonstrating the various winding methods of a fiber. It is sectional drawing which shows the structural example vicinity of the nozzle | cap | die of a tank. It is a figure which shows roughly the mode of winding of the helical layer in one Embodiment of this invention. It is sectional drawing of the nozzle | cap | die vicinity of the tank shown in FIG. It is a graph which shows an example in the case of decreasing continuously the coverage with the fiber of a helical layer. It is a graph which shows an example in the case of decreasing the coverage by the fiber of a helical layer in steps. It is a figure which shows an example of FW (filament winding) apparatus. It is a figure which shows a mode that a fiber is wound around the outer periphery of a liner using the fiber guide apparatus of FW apparatus. It is a figure which shows the mode of winding of the helical layer in the conventional tank for reference. It is sectional drawing of the nozzle | cap | die of the tank shown in FIG.

Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

1 to 9 show an embodiment of a tank and a manufacturing method thereof according to the present invention. Below, it demonstrates, exemplifying the case where the tank (high pressure tank) 1 concerning this invention is applied to the high pressure hydrogen tank as a hydrogen fuel supply source. The hydrogen tank can be used in a fuel cell system or the like.

The tank 1 includes, for example, a cylindrical tank body 10 having both ends substantially hemispherical, and a base 11 attached to one end of the tank body 10 in the longitudinal direction. In the present specification, the substantially hemispherical portion is referred to as a dome portion, and the cylindrical body portion is referred to as a straight portion, which are denoted by reference numerals 1d and 1s, respectively (see FIGS. 1 and 2). Moreover, although the tank 1 shown in this embodiment has the caps 11 at both ends, for the sake of convenience of explanation, the forward direction of the X axis (direction indicated by the arrow) in FIG. The side and the negative direction will be described as the base end side. The positive direction (the direction indicated by the arrow) of the Y axis perpendicular to the X axis indicates the tank outer peripheral side.

The tank body 10 has, for example, a two-layer wall layer, and has a liner 20 that is an inner wall layer and, for example, an FRP layer 21 that is a resin fiber layer (reinforcing layer) that is an outer wall layer on the outer side. The FRP layer 21 is formed of, for example, only the CFRP layer 21c, or the CFRP layer 21c and the GFRP layer 21g (see FIG. 1).

The liner 20 is formed in substantially the same shape as the tank body 10. The liner 20 is made of, for example, polyethylene resin, polypropylene resin, or other hard resin. Alternatively, the liner 20 may be a metal liner formed of aluminum or the like.

A folded portion 30 that is bent inward is formed on the tip end side of the liner 20 having the base 11. The folded portion 30 is folded toward the inside of the tank body 10 so as to be separated from the outer FRP layer 21. The folded portion 30 has, for example, a reduced diameter portion 30a that gradually decreases in diameter as it approaches the folded tip, and a cylindrical portion 30b that is connected to the distal end of the reduced diameter portion 30a and has a constant diameter. The cylindrical portion 30b forms an opening of the liner 20.

The base 11 has a substantially cylindrical shape and is fitted into the opening of the liner 20. The base 11 is made of, for example, aluminum or an aluminum alloy, and is manufactured in a predetermined shape by, for example, a die casting method. The base 11 is fitted into an injection-molded split liner. Further, the base 11 may be attached to the liner 20 by insert molding, for example.

In addition, the base 11 has a valve fastening seat surface 11a formed on the tip side (outside in the axial direction of the high pressure tank 1), for example, and on the rear side (inside in the axial direction of the high pressure tank 1) of the valve fastening seat surface 11a. An annular recess 11 b is formed with respect to the axis of the high-pressure tank 1. The dent 11b is convexly curved on the shaft side and has an R shape. Similarly, the vicinity of the tip of the R-shaped FRP layer 21 is in airtight contact with the recess 11b.

For example, the surface of the recess 11b that contacts the FRP layer 21 is provided with a solid lubricating coating C such as a fluorine-based resin. Thereby, the friction coefficient between the FRP layer 21 and the recessed part 11b is reduced.

The rear side of the recessed portion 11b of the base 11 is formed to fit, for example, the shape of the folded portion 30 of the liner 20, and for example, a flange portion (crest portion) 11c having a large diameter is formed continuously from the recessed portion 11b. A cap cylindrical portion 11d having a constant diameter is formed rearward from the flange portion 11c. The reduced diameter portion 30a of the folded portion 30 of the liner 20 is in close contact with the surface of the flange portion 11c, and the cylindrical portion 30b is in close contact with the surface of the cap cylindrical portion 11d. Seal members 40 and 41 are interposed between the cylindrical portion 30b and the base cylindrical portion 11d.

The valve assembly 50 controls the supply and discharge of the fuel gas between the external gas supply line (supply path 22) and the inside of the tank 1. Seal members 60 and 61 are interposed between the outer peripheral surface of the bubble assembly 50 and the inner peripheral surface of the base 11.

The FRP layer 21 is formed by, for example, FW molding (filament winding molding), winding a resin-impregnated fiber (reinforcing fiber) 70 around the outer peripheral surface of the liner 20 and the recess 11b of the base 11 and curing the resin. Has been. For the resin of the FRP layer 21, for example, an epoxy resin, a modified epoxy resin, an unsaturated polyester resin, or the like is used. Further, as the fiber 70, carbon fiber (CF), metal fiber, or the like is used. At the time of FW molding, the outer periphery of the liner 20 is moved by moving the guide of the fiber 70 along the tank axis direction while rotating the liner 20 around the tank axis (indicated by reference numeral 12 in FIGS. 1 and 2). The fiber 70 can be wound around. In practice, a fiber bundle in which a plurality of fibers 70 are bundled is generally wound around the liner 20. However, in this specification, the fiber bundle is simply referred to as a fiber including the case of a fiber bundle.

Next, an example of the structure of the tank 1 that optimizes the coverage of the fibers 70 in the fiber layers 71 and 72 of the FRP layer 21 will be described (see FIG. 4 and the like).

Here, an example of an FW (filament winding) device for winding the fiber 70 will be briefly described. The FW device 80 shown in FIGS. 8 and 9 reciprocates the guide device (referred to as “eye opening”) 81 of the fiber 70 along the tank axial direction while rotating the liner 20 around the tank shaft 12. Thus, the fiber 70 is wound around the outer periphery of the liner 20. The winding angle of the fiber 70 can be changed by changing the relative speed of the movement of the guide device 81 with respect to the rotational speed of the liner 20. The guide device 81 is operably supported by a jig, for example.

As described above, the tank 1 is formed by winding a fiber (for example, carbon fiber) 70 around the outer periphery of the liner 20 and curing the resin. Here, there are a hoop winding and a helical winding for winding the fiber 70 (see FIG. 2). , The low-angle helical layer 70HL) is formed. In the former hoop winding, the fiber 70 is wound around the straight portion (tank body portion) 1 s of the tank 1 like a coil spring to tighten the portion, and the force in the positive direction of the Y axis by the gas pressure (outward in the radial direction) A force to counteract the force to spread) is applied to the liner 20. On the other hand, the latter helical winding is a winding method whose main purpose is to fasten the dome portion 1d, and the fiber 70 is entirely wound around the tank 1 so as to be caught by the dome portion 1d. This contributes to improving the strength of the portion 1d. In addition, an acute angle (of which an acute angle is formed) between a string 70 of a fiber 70 wound like a coil spring (a thread line in a screw) and a center line of the tank 1 (tank shaft 12). 2) is the “winding angle with respect to the tank shaft (12)” of the fiber 70 referred to in the present specification, which is indicated by the symbol α in FIG.

Of these various winding methods, the hoop winding is a method in which the fiber 70 is wound substantially perpendicularly to the tank shaft 12 in the straight portion, and a specific winding angle at that time is, for example, 80 to 90 ° (see FIG. 2). ). Helical winding (or impeller winding) is a winding method in which the fibers 70 are wound around the dome portion, and the winding angle with respect to the tank shaft 12 is smaller than that in the case of hoop winding (see FIG. 2). If the helical winding is roughly divided into two types, there are two types: high angle helical winding and low angle helical winding. Among them, the high angle helical winding has a relatively large winding angle with respect to the tank shaft 12, and specific examples of the winding angle are as follows. 70 to 80 °. On the other hand, the low-angle helical winding has a relatively small winding angle with respect to the tank shaft 12, and a specific example of the winding angle is 5 to 30 °. Incidentally, the winding angle when the fiber 70 is parallel to the tank shaft 12 is 0 °, and the winding angle when the fiber 70 is wound around in the circumferential direction is 90 °. In the present embodiment, the term “low angle helical winding” including helical winding at a winding angle of 0 to 5 ° is referred to.

In the present specification, a helical winding at a winding angle of 30 to 70 ° between them may be referred to as a medium angle helical winding. Further, the helical layers formed by the high angle helical winding, the medium angle helical winding, and the low angle helical winding are respectively a high angle helical layer (indicated by reference numeral 70HH), a medium angle helical layer (see FIG. 2), and a low angle helical layer ( This is indicated as 70LH. Further, the folded portion in the tank axial direction in the dome portion 1d of the high angle helical winding is referred to as a folded portion (see FIG. 2).

In general, the hoop winding is a winding method that allows the fibers 70 to be wound spirally while adjoining the fibers 70 so that the fibers 70 are not stacked and the unevenness is not generated. On the other hand, the helical winding is generally intended to tighten the dome portion, and it is difficult to reduce the stacking and unevenness of the fibers 70, or sufficient consideration is given to reducing them. There is no winding method. The hoop winding and the helical winding are appropriately combined according to specifications such as the axial length and diameter of the tank 1, and the hoop layer 70P and the helical layer 70H are stacked around the liner 20 (see FIG. 1 and the like). At this time, making the coverage by the fibers 70 (the ratio of the one-side surface area of the fibers 70 wound around the layer to the surface area of the straight portion 1s of the tank 1) uniform in each layer increases the amount of the fibers 70 used. However, it is disadvantageous in that it is difficult to obtain sufficient fiber strength. In this respect, in the present embodiment, the fiber layer in the helical layer 70H is configured such that the coverage rate by the helical layer 70H with respect to the straight portion (body portion) 1s of the tank 1 is increased toward the inner layer side and gradually decreased toward the outer layer side. The strength generation rate is effectively improved (see FIG. 4 and the like).

That is, when the fiber 70 is wound in a state in which the cover rate in the helical layer 70H is, for example, uniformly 100% or more as in the conventional case (see FIG. 8), the fiber 70 that is wound on the outer layer side is particularly concerned. It is difficult to sufficiently exert the strength of the FRP layer 21 with respect to the fiber strength occurrence rate, and as a result, the physique and mass of the tank 1 may increase (FIG. 9). reference). On the other hand, in the case of the tank 1 of the present embodiment, the coverage ratio of the helical layer 70H with respect to the straight portion 1s is increased toward the tank inner layer side (lowered from the tank inner layer side toward the outer layer side) ( (See FIG. 4). In such a case, the fiber strength occurrence rate in the helical layer 70H can be effectively improved, and as a result, the physique or mass of the tank 1 can be prevented from becoming too large while ensuring the fiber strength occurrence rate. That is, in the present embodiment, the cover rate is optimized so that the FRP layer 21 can be formed thinner than the conventional one while ensuring the fiber strength generation rate (see FIG. 5). It is possible to reduce the size of the entire tank while maintaining (internal capacity), and it is possible to suppress an increase in physique without obtaining sufficient fiber strength (so-called enlargement of the tank 1). . This is particularly effective under the current situation where the tank 1 is required to have a larger size, a higher pressure, and a reduced number of tanks. Further, when the tank 1 is used as, for example, a hydrogen supply tank for a fuel cell vehicle, it can contribute to extending the cruising distance of the vehicle.

Here, the aspect of the change in the coverage by the fibers 70 is not particularly limited, and may be gradually reduced from the inner layer to the outer layer of the FRP layer 21 (see FIG. 6) or stepwise. It may be decreased (see FIG. 7). Further, the rate of decrease is not particularly limited, and may be a constant rate or may be changed in the middle. Further, there is no particular limitation as to how much the coverage in the outermost helical layer 70H is to be made. In this embodiment, the cover ratio is 50% (as an example, the case where the one-side surface area of the wound fiber 70 and the gap between the fibers 70 are substantially equal as in this embodiment) is exemplified ( The cover rate in the outermost layer may be higher or lower than this, and the layer having a cover rate of 50% may be used as an intermediate layer instead of the outermost layer.

However, in any of the above-described forms, it is preferable that the fibers 70 are evenly wound in one helical layer 70H (see FIG. 4). By winding so that the intervals between the fibers 70 are equal, the fiber strength generation rate by the fibers 70 can be made more uniform.

In the tank 1 of the present embodiment described above, the following effects can be obtained. That is, the fiber 70 is wound so that the covering ratio of the helical layer 70H to the straight portion 1s of the tank 1 with respect to the straight portion 1s of the tank 1 is lower on the outer layer side than the inner layer side of the FRP layer 21, and the fiber strength generation rate is more effective. Therefore, the use efficiency of the fiber 70 is improved. Moreover, it can suppress that the physique or mass of the tank 1 becomes large by this.

The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the case where the present invention is applied to a hydrogen tank that can be used in a fuel cell system or the like has been described as an example. However, a tank for filling a fluid other than hydrogen gas, for example, CNG (compressed natural gas) Of course, the present invention can also be applied to a high-pressure vessel used in a CNG vehicle that uses) as a fuel.

Furthermore, the present invention can be applied to things other than a tank (pressure vessel), for example, a cylinder (including a cylindrical part) such as a long object or a structure having an FRP layer. For example, when the FRP layer 21 having the helical layer 70H or the hoop layer 70P is formed by wrapping the fiber 70 around a mandrel (such as a mandrel) or a mold by helical winding or hoop winding, a hoop layer is formed. The fiber strength of the fiber strength is improved by, for example, arranging 70P on the inner side to form an inner layer, or arranging the fiber folded end portion 70e so as to draw a trajectory that is narrowed toward the outer layer (defined as a set of all points satisfying a certain condition). It is possible to achieve the same operational effects as in the above-described embodiment, such as improving the expression efficiency. Specific examples of the cylinder in the case where the present invention is applied to the cylinder as described above include exercise equipment such as a golf club shaft and carbon bat, leisure equipment such as a fishing rod, engineering products such as plant equipment, and building materials. Can be mentioned.

Although not described in detail in the above-described embodiment, it is also preferable that at least a part of the helical layer 70H is a smooth helical layer to reduce unevenness that may occur in the hoop layer 70P adjacent to the outside. The smooth helical layer 70 </ b> H here is a layer formed by helical winding so as to reduce the overlap of the fibers 70 in the layer, and in principle, the next fiber 70 is aligned next to the adjacent fibers 70. Is wound, and the way the fibers 70 overlap is different from the conventional helical layer (uneven helical layer). As described above, when a part of the helical layer 70H is a smooth helical layer and the hoop layer 70P is formed by hooping the fibers 70 outside the smooth helical layer 70H, the fibers 70 in the hoop layer 70P are formed. Structural bending (undulations) or undulations and undulations can be reduced. That is, since the surface (surface layer) of the smooth helical layer 70H is smoother than the conventional surface, in the hoop layer 70P formed on the smooth surface, the bending (undulation) of the structural fibers 70 caused by unevenness. ) Is reduced. Thus, by suppressing the structural bending (undulation) of the fiber 70 of the hoop layer 70P, the fatigue strength of the fiber 70 can be improved, and the hoop layer 70P is thinned and has a high Vf (fiber volume). Content ratio) and the burst strength is improved. In addition, the fact that the helical layer 70H itself is smooth can improve the burst strength through thinning the layer and increasing Vf. Vf represents the fiber volume content. When the value (Vf value) increases, the fiber content increases and the resin content decreases. If the value of Vf is too high, fatigue durability deteriorates, and if the value is too low, the outer diameter of the tank increases.

In the tank 1 described above, the winding start of the liner 20 can be either the fiber 70 forming the helical layer 70H or the fiber 70 forming the hoop layer 70P. In this way, by appropriately changing the fiber 70 at the start of winding, it is possible to set the break start position when the tank 1 should break. As described above, both the helical layer 70H and the hoop layer 70P have a greater contribution to the tank strength as the layer located on the inner side (the layer closer to the liner 20). Therefore, for example, by forming the winding start with respect to the liner 20 as the forming fiber 70 of the hoop layer 70P and making the fiber strength with respect to the straight portion 1s larger than that with respect to the dome portion 1d, the break start position becomes the dome portion 1d in advance. It is possible to set.

The present invention is suitable when applied to a tank having an FRP layer, and further to a cylindrical body such as a long object or a structure.

DESCRIPTION OF SYMBOLS 1 ... Tank, 1s ... Straight part (torso part), 20 ... Liner, 21 ... FRP layer, 70 ... Fiber, 70H ... Helical layer, 70P ... Hoop layer

Claims (6)

A tank having a liner, and an FRP layer composed of a hoop layer and a helical layer formed by winding fibers on the outer periphery of the liner,
A tank in which the coverage of the helical layer by the fibers to the body portion of the tank is lower on the outer layer side than on the inner layer side of the FRP layer. The tank according to claim 1, wherein the coverage by the helical layer is continuously reduced. The tank according to claim 1, wherein the coverage by the helical layer is decreased stepwise. The tank according to claim 2 or 3, wherein a rate of decrease in the cover rate is constant. The tank according to claim 2 or 3, wherein a rate of decrease in the coverage rate changes midway. In a method of manufacturing a tank having a liner and an FRP layer composed of a hoop layer and a helical layer formed by winding fibers on the outer periphery of the liner,
A method for manufacturing a tank, wherein when the fiber is wound, a covering ratio of the helical layer to the body portion of the tank is lower on the outer layer side than on the inner layer side of the FRP layer.

Images